<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script crossorigin src="https://unpkg.com/react@17/umd/react.development.js"></script>
    <script crossorigin src="https://unpkg.com/react-dom@17/umd/react-dom.development.js"></script>
<!--    用于解析ES6-->
    <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
    <style>
        .red {
            color: red;
        }
    </style>
</head>
<!--ES6 -->
<!--条件处理-->
<body>
    <div id="app"></div>
    <script type="text/babel">

        function Login(){
            return <button>Login</button>
        }
        function Logout(){
            return <button>Logout</button>
        }
        class Template extends React.Component {
            state = {
                isLogin: false
            }
            render(){
                const islogin = this.state.isLogin

                return <div>
                    {islogin ? <Login/> : <Logout/>}
                </div>
            }
        }
        ReactDOM.render(<Template/>,document.getElementById('app'))
    </script>
</body>
</html>